Help in post-layout simulations

[Maithreyi]

Can anyone please help me out in my layout design.

I have extracted parasitics for my design and when I compare the results(Gain, NF etc.) of prelayout and postlayout simulations, they are not matching.

I have observed lot of variations in prelayout and postlayout simulation results.

How can I match the postlayout simulations with that of prelayout?

Please help me.

Thanks in advance........

 

[Braski]

you should control the report of the PEX at first, and find the larger parasitics, and try to evaluate their effect. I think it can be a good idea to evaluate atfirst single blocks performances, in order to find if there are some critical issuesinthe building blocks or it is a problem of interconnections.

 

[MNBahr]

It is expected to have the simulation results different because of parasitic capacitance and their effects, first you have to know which capacitance have greater contribution and try to remove them, if u failed you have to consider their values in your design objectives/specifications